cellulose cel·lu·lose (sěl'yə-lōs', -lōz')n. A complex carbohydrate that is composed of glucose units, forms the main constituent of the cell wall in most plants, and is important in the manufacture of numerous products, such as pharmaceuticals.

A carbohydrate that is a polymer composed of glucose units and that is the main component of the cell walls of most plants. It is insoluble in water and is used to make paper, cellophane, textiles, explosives, and other products.